1. Field of Invention
The present invention relates to threaded oilfield tubulars. The present invention is directed to a tool for applying torque and rotation to an add-on pipe segment to make up or break out a threaded pipe connection or to rotate a pipe string. More specifically, the present invention is directed to a tool having one or more elastomeric sprags oriented on the tool for engaging and rotating an add-on pipe segment in a first rotational direction, but not in the opposite rotational direction. Additional sprags may be disposed on a separate portion of the tool for selectively providing for the capacity to rotate an add-on pipe segment in the opposite direction.
2. Description of the Related Art
Conventional power tongs are machines used on a rig to grip the exterior surface of an add-on pipe segment and rotate the add-on pipe segment about its axis to threadably make-up a connection between the add-on pipe segment and an aligned pipe string. The power tong generally has a throat through which the add-on pipe segment may be introduced between gripping jaws of the power tong. The gripping jaws are pivotally securable to a gripping jaw retainer that supports the jaws in position to grip, rotate and torque the add-on pipe segment by powered rotation of a surrounding ring gear. The ring gear may be rotatable using hydraulically-powered pinion gears to make up the threaded connection. After the threaded connection is torqued, a conventional power tong must generally be moved back away from well center for subsequent well operations. Conventional power tongs may be movably disposed on a track or in a groove that provides for automated advancement to and retraction from well center.
A power tong may cooperate with an elevator that kicks out from well center to secure to and position an add-on pipe segment for being joined to the pipe string. Elevators may be suspended from a vertically movable top drive or a block using a pair of elongate bails. After an add-on pipe segment is joined to the proximal end of the pipe string, the elevator may be used to support the pipe string within the borehole so that the spider may disengage and the lengthened pipe string may be further installed in the borehole by lowering the elevator and the pipe string through the disengaged spider. This process may be repeated until the pipe string reaches a desired length.
Conventional power tongs are generally large machines that consume a large portion of space on the rig floor, and some rigs may need to be retrofitted to accommodate conventional power tongs that operate on tracks or in grooves on the rig floor. Conventional power tongs may obstruct the view on the rig floor and often cause unwanted marks on the exterior of the add-on pipe segment and/or the pipe string. Conventional power tongs may present an obstruction on rigs equipped with elevators that kick out from well center to support and position add-on pipe segments at well center for being joined into the pipe string.
Other power tongs may comprise tools that internally grip the add-on pipe segment. Internally gripping power tongs, which may include casing running tools, often employ complex mechanisms for deployment of pipe gripping jaws. Actively deployable gripping jaws may deploy by operation of cams, cylinders or axially movable mandrels. These mechanisms result in additional cost, weight and maintenance, and often require a source of external power for deployment and retraction of gripping jaws to engage and release an add-on pipe segment, respectively.
What is needed is a method of rotating and torquing an add-on pipe segment to make up a threaded connection to a pipe string that utilizes substantially less rig floor space than a conventional power tong. What is needed is a power tong that can rotate and torque an add-on pipe segment using a top drive. What is needed is a power tong that can internally or externally engage and apply torque to an add-on pipe segment for making up or breaking out a threaded connection, thereby eliminating the cost, weight and maintenance of more complex actuated gripping jaws, and avoiding the need for coupling the tool to a source of power for engaging or retracting the tool. What is needed is a power tong that cooperates with elevators that kick out from well center to secure to and position add-on pipe segments at well center for being joined into the pipe string. What is needed is a tool for gripping and rotating an add-on pipe segment that does not mark or scar the pipe wall, and that does not cause damage to the threads that form the connection upon insertion of the tool into the bore of the add-on pipe segment.